Reviewers: Jakob,
Message:
PTAL.
In some other CL, we might want to switch the entire Zone to size_t
Description:
Use unsigned integer arithmetic in Zone::NewExpand.
BUG=328202
[email protected]
LOG=N
Please review this at https://codereview.chromium.org/108783005/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files (+19, -10 lines):
M src/zone.cc
Index: src/zone.cc
diff --git a/src/zone.cc b/src/zone.cc
index
9ee00edcba16d5970cb592d78c13b7194ed8c0bb..417f895e5ae29536cf29c4f7eb42344c57d55277
100644
--- a/src/zone.cc
+++ b/src/zone.cc
@@ -185,25 +185,31 @@ Address Zone::NewExpand(int size) {
// except that we employ a maximum segment size when we delete. This
// is to avoid excessive malloc() and free() overhead.
Segment* head = segment_head_;
- int old_size = (head == NULL) ? 0 : head->size();
- static const int kSegmentOverhead = sizeof(Segment) + kAlignment;
- int new_size_no_overhead = size + (old_size << 1);
- int new_size = kSegmentOverhead + new_size_no_overhead;
+ const size_t old_size = (head == NULL) ? 0 : head->size();
+ static const size_t kSegmentOverhead = sizeof(Segment) + kAlignment;
+ const size_t new_size_no_overhead = size + (old_size << 1);
+ size_t new_size = kSegmentOverhead + new_size_no_overhead;
+ const size_t min_new_size = kSegmentOverhead + static_cast<size_t>(size);
// Guard against integer overflow.
- if (new_size_no_overhead < size || new_size < kSegmentOverhead) {
+ if (new_size_no_overhead < static_cast<size_t>(size) ||
+ new_size < static_cast<size_t>(kSegmentOverhead)) {
V8::FatalProcessOutOfMemory("Zone");
return NULL;
}
- if (new_size < kMinimumSegmentSize) {
+ if (new_size < static_cast<size_t>(kMinimumSegmentSize)) {
new_size = kMinimumSegmentSize;
- } else if (new_size > kMaximumSegmentSize) {
+ } else if (new_size > static_cast<size_t>(kMaximumSegmentSize)) {
// Limit the size of new segments to avoid growing the segment size
// exponentially, thus putting pressure on contiguous virtual address
space.
// All the while making sure to allocate a segment large enough to
hold the
// requested size.
- new_size = Max(kSegmentOverhead + size, kMaximumSegmentSize);
+ new_size = Max(min_new_size, static_cast<size_t>(kMaximumSegmentSize));
}
- Segment* segment = NewSegment(new_size);
+ if (new_size > INT_MAX) {
+ V8::FatalProcessOutOfMemory("Zone");
+ return NULL;
+ }
+ Segment* segment = NewSegment(static_cast<int>(new_size));
if (segment == NULL) {
V8::FatalProcessOutOfMemory("Zone");
return NULL;
@@ -213,7 +219,10 @@ Address Zone::NewExpand(int size) {
Address result = RoundUp(segment->start(), kAlignment);
position_ = result + size;
// Check for address overflow.
- if (position_ < result) {
+ // (Should not happen since the segment is guaranteed to accomodate
+ // size bytes + header and alignment padding)
+ if (reinterpret_cast<uintptr_t>(position_)
+ < reinterpret_cast<uintptr_t>(result)) {
V8::FatalProcessOutOfMemory("Zone");
return NULL;
}
--
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